http://www.gutenberg.org/ebooks/subject/13988.opds 2024-11-09T16:29:45Z Books about Word problems (Mathematics) (sorted by popularity) Free eBooks since 1971. Project Gutenberg https://www.gutenberg.org webmaster@gutenberg.org https://www.gutenberg.org/gutenberg/favicon.ico 25 1 2024-11-09T16:29:45Z https://sendtokindle.compellingsciencefiction.com/ebooks/16527.opds 1001 задача для умственного счета (Russian) Sergei Aleksandrovich Rachinskii